When the library reads the frequency and mode data from the rig, it does not check to see if the data are valid. If the rig is not connected, the library reads four bytes anyway and it will get ff ff ff ff (hex) for the frequency (whereas a valid value would be e.g. 14 02 50 00).
The code which converts this to a frequency treats this data as if it were valid hex digits and the result of converting that is 166 666 665.
If you get that value when you connect your rig, then it isn't wired properly.
Pete